Electrical receptacle



Sept, 17, 1940. I G. BBENANDER ELECTRICAL RECEPTACLE Filed Feb. 23, 1939Invetr: George B. Benarwder,

b 7;/ 5J W1 y s Attorney.

Patented Sept. 17, 1940 4ELECTRICAL REClEPTACLE George B. Benander,Oaklawn, R. I., assigner to Monowatt Electric Corporation, R. I., acorporation of Connecticut Providence,

Application February 23, l1939, Serial No. 257,855

9 Claims.

The present invention relates to electrical receptacles, and moreparticularly to a receptacle having means for locking an attachment plugcap thereto.

It is an object of this invention to provide a receptacle having lockingmeans adapted to cooperate with the blades of a standard attachment plugcap.

It is another object of this invention to provide a simple and ruggedreceptacle construction which is economical to manufacture.

It is a further object of this invention to provide a receptacle havingan actuating member adapted to be rotated by the blades of an`attachment cap positioned in the receptacle, the rotation of theactuating member being effective to force a locking member intoengagement with one of the blades of the attachment cap.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds, reference being had tothe accompanying drawing, in which Fig. 1 is a front elevation of awallplate and receptacle embodying the present invention and showing anattachment plug cap locked to the receptacle; Fig. 2 is a sectional viewtaken along the line 2 2 of Fig. l; Fig. 3 is a sectional view takenalong the line 3-3 of Fig. 1; Fig. Liis a rear view of the wall platehaving its edge portions partially broken away; Fig. 5 is a frontelevational view of the l receptacle body showing the stationary contact"iro and terminal structure, and Fig. 6 is a perspective view of one ofthe actuating members provided for operating the locking means.

Referring to the accompanying drawing, a housing for the parts of thereceptacle. is provided by a wall plate III and a receptacle body I I,both of which are formed of a comparatively rigid insulating materialsuch as a phenolic cfondensation product. 'Ihe receptacle body which isrecessed from its upper face to form a substantially hollow body issecured 'to the rear face of the wall plate by a bolt I2 having threadedengagement with an insert I3 -centrally located in the wall plate. Anupstanding bead I4 is formed on the rear face of the wall plate toprovide a bearing surface for the upper edge of the side Walls I5 of thereceptacle body. Projecting lugs I6 on the bead I 4 engage correspondingslots I1 in the walls of the receptacle body to position the parts ofthe housing relative to fone another. Cross-like structures I8 and I9are-molded integrally with the wall plate and receptacle bodyrespectively to strengthen the molded parts and --form an additionalbearing surface between the Wall plate and receptacle body adjacent theholding bolt I2. While in the constructiony described above the covermember for the receptacle body alsoforms a wall plate, itis appar-entthat a se arate cover may be provided if desired. ,f

The stationary contact and terminal structure of the receptacle isprovided by a pair of conducting strips 20 each of which comprises acentral offset terminal porton 2I and a pair of curved Contact surfaces22 formed at each end thereof. The lcontact and terminal strips arepreferably sheet metal stampings of good lconducting material. Thestrips are mounted -edgewise in the receptacle body adjacent theopposite side walls with the oifset terminal portions positioned in theiii recesses 23 which 'are formed in the middle of the side walls of thereceptacle body. The contact portions of the conducting strips 20 arelaterally unsupported and are free-to engage resiliently the contactblades of an-attachinent cap when they are positionedl in thereceptacle. A longitudinally extending bead 24 is provided on the floor25 oi the receptacle adjacent the inner surface of each of theconducting strips to hold them against theabutments 26 formed-adjacentthe recesses 23 by thickened v portions of the side walls I5.Corresponding longitudinally extending beads 2l are formed on the innerface of the the cap then given a partial turn'to move the blades intoengagement with the stationary contacts of the receptacle, the movementalso being effective -to project a locking member into the usual openingformed near the end of a blade of a standard attachment plug cap. In thedrawing, a duplex receptacle is shown but, since both of the outlets andtheir associated locking mechanisms are of the same construction, onlyone will be described. A locking member in the form of a substantiallyL-shaped pin has one arm 30 journaled in a suitable openingy 3| formedin an upstanding boss 32 which is preferably molded integrally with thefloor of the receptacle body. The other arm 33 of the locking kmemberpro- Iii) jects laterally beyondthe edgeof the boss in a plane parallelto the floor of the receptacle. i

For operating the locking pin an actuating member in the form of a plug34 rof insulating material of generally cylindrical shape is provided.The outer end of the plug is mounted for rotation in a suitable circularopening 35 formed in the wall plate. A ilange 36 extending from theouter wall of the insulating plug 34 cooperates with a shoulder 3l onthe inner face of the wall plate to hold the plug against the boss 32formed on the iioor of the receptacle body. A driving connection betweenthe plug 34 and the locking pin is provided by the spaced depending ribs38 and 39 which extend divergently across the lower face of theinsulating plug 34 and define a tapered groove 40 for the reception ofthe laterally extending arm 33 of the locking pin. The plug 34 isprovided with axially extending recesses or openings 4| and 42diametrically opposite points on its outer surface for the reception ofthe contact blades of an attachment plug cap. The attachment plug capmay be of any suitable construction and as illustrated comprises a bodyof insulating material 43 having a pair of spaced parallel contactblades 44 which in accordance with the usual practice are provided neartheir free ends with a small circular opening 45. The side walls of therecesses are spaced' to cooperate with the contact blades of theattachment cap to form a driving connection between the insulating plugand the attachment cap. When the contact blades 44 of the attachment capare positioned in the recesses 4| and 42 they extend into the receptaclebody adjacent the opposite side walls 46 of the insulating plug which inthe preferred construction illustrated form extensions of the bottomwalls of the recesses 4| and 42.

As shown in Figs. 2 and 4 the boss 32 projecting from the floor` of thereceptacle body and the locking pin, which in the construction shown ispivoted on the boss, are positioned eccentrically with respect to theactuating member or plug 34. 'Ihis eccentric mounting causes relativetransverse movement between the insulating plug and the locking member.and serves to move the locking pin from'ts unlocked to its lockedposition in responseto rotation of the insulating plug. As used abovethe word transverse is intended to indicate movement in a planegenerally perpendicular to the axis of rotation of the plug 34 and isnot meant to be limited to movement along either axis of the receptaclebody. In the drawing, the outlet in the upper portion of Figs. l, 2 and4 is shown with its parts in looked position, whilethe parts of theoutlet shown in the lower portions of these iigures are shown in theunlocked position. From an inspection of Fig. 4 it is apparent that thearm 33 lies in ar plane perpendicular to the axis of rotation of theplug 34 and is of such length that its outer end does not project beyondthe lower edge of the wall 46 of. the insulating plug rwhen the arm 33extends along the longitudinal axis of the receptacle body as it doeswhen the locking mechanism is .in its unlocked position. When the plug34 is rotated a quarter turn in a counterclockwise direction as viewedin Fig. 4, the outer end of the arm 33 moves beyond the wall 46 and intoalignment with recess 4| formed in the insulatingplug.` As illustratedin Fig. 3, this movement is effective to move the outer end of the arm33 into the opening 45 of the contact blade positioned in the recess 4|.The groove 40 formed on the lower surface' of the insulating plug 34 isonly slightly wider at one end than the arm 33 of the locking pin inorder to limit the circumferential movement of the arm relative to theplug. Near the center of the plug the recess is wide enough toaccommodate the shifting of the plug with respect to the locking pinthat results from the eccentric mounting of the pin and plug.

In using a receptacle with the locking feature of the present inventionthe contact blades 44 of an attachment plug cap are inserted in therecesses 4| and 42 of the insulating plug 34 when the plug is in theposition shown in the lower portions of Figs. 1, 2 and 4. At this timethe end of the locking arm 33 is flush with the lower edge of the wall46 of the insulating plug 34.`

The blades 44 extend into the recessed receptacle body beyond the loweredge of the insulating plug 34 and lie in the space surrounding theinsulating plug 34 and the boss 32. The attachment cap is then rotated aquarter turn in a clockwise direction as viewed in Fig. 1, and becauseof the engagement of the contact blades with the walls of the recesses4| and 42 the insulating plug 34 is rotated a like amount. Durf ingrotation of the insulating plug the arm 33 of the locking pin is engagedby one of the depend-ing ribs 38.0n the face of the insulating plug andmoved to the position shown in Fig. 3f It is seen that the end of thelocking arm is moved beyond the edgeof the insulating plug into .thepath of the contact blade and into the opening 45 formed near the endthereof. The pin which is held in the housing by the insulating plugengages the wall of the opening 46 and prevents the attachment cap frombeing accidentally withdrawn from the receptacle. When the attachmentcap and plug 34 are rotated :from their unlocked to their lockedposition the contact blades 44 are moved into engagement with theresilient contacts 20 which aid in positioning the attachment vplug caprelative to the receptacle and form resilient means opposing theaccidental rotation of the attachment plug cap and the insulating plug34. To release the plug cap' it is only necessary to rotate it in areverse direction for a quarter turn thus returning the lockingmechanism to its nunlocked position as shown in the lower portion ofFig. 4.'

With the construction described above a receptacle is provided withmeans forv positively locking a standard attachment plug vcap thereto.At the same time, a relatively simple and rugged structure is providedwhich may be manufactured at lowcost.

' kWhat I claim as new and desire to secure by Letters Patent of theUnited States, is:

1. In a plug receptacle, a housing, a first member of insulatingmaterial rotatably mounted in said housing and having recesses formedtherein `for the reception of the contact blades of an attachment plugcap, a second insulating member projecting from the floor of saidhousing and positioned eccentrically with respect to said firstmentioned member whereby rotation of said iirst mentioned memberrelative to the other of said members causes relative transversemovement between said members, an elongated locking pin carried by oneof said members and extending perpendicularly to the axis, of rotationof said rst mentioned member, and bodily movable relative to said firstmember and in a plane normal to the axis of rotation of said rst memberinto engagement with a contact blade positionedV in one of said recessesin response to rotation of said rst member of insulating material.

2. In a plug receptacle, a housing, a plug rol tatably mounted in saidhousing, said plug having spaced axially extending openings formedtherein for the reception of the contact bladesl of an attachmentplugcap, an elongated locking member rotatably mounted in said housing andextending perpendicularly to the axis of rotation of said plug and adriving connectionv between said plug and said locking member forrotating said locking member in response to rotation of said plug andpermitting said locking member to move bodily relative to said plug andin a direction transverse to the axis of said plug into engagement witha contact blade positioned in one of said openings in response torotation of said plug.

3. In a plug receptacle, a housing recessed to receive the contactblades of an attachment plug cap, a member of insulating materialrotatably mounted in said housing, a locking pin mounted' in saidhousing and extending in a plane perpendicular to the axis of rotationof said member of insulating material, said locking pin having an endflush with an outer side wall of vsaid member of insulating materialwhen said member is in one position, and a driving connection betweensaid member and said locking pin for rotating 'said pin with saidmember, the axes of rotation of said member and said pin beingeccentrically located whereby said end of said locking pin moves beyondsaid outer side wall into locking engagement with a Contact bladereceived in said housing when said member is rotated to anotherposition.

4. In a plug receptacle, a receptacle body recessed from one face toreceive the contact blades of an attachment plug cap, an actuatingmember mounted in said body for rotation about an axis substantiallyperpendicular to said one face, a locking member rotatably mounted insaid housing, and a driving connection between said actuating member andsaid locking member, the axes of rotation of said actuating member andsaid locking member being spaced apart transversely whereby rotation ofsaid actuating member is effective to move said locking membertransversely with respect to said actuating member and into engagementwith a contact blade received in said body.

5. In a plug receptacle, a housing, arotatable actuating member ofinsulating material mounted in said housing, said actuating memberhaving openings formed therein for the reception of the contact bladesof an attachment plug cap, locking f means mounted in said housing forrotation about an axis parallel to the axis of rotation of saidactuating member of insulating material, and means on said actuatingmember for engaging said locking member to transmit rotary motiontherebetween, the axes of rotation of said member and said locking meansbeing spaced apart whereby rotation of said actuating member causesrelative transverse movement between said locking means and saidactuating member and said locking means is moved into engagement with acontact blade positioned in one of said recesses.

6. In a plug receptacle, a housing of insulating material, a plug ofinsulating material rotatably mounted in said housing, said plug havinga pair of recesses formed therein for the reception of the spacedContact blades of an attachment plugcap, asubstantially L-shaped pinhaving one arm journaled in the oor of said body, and means on said plugfor engaging the other arm of said L- shaped pin to rotate said pin inresponse to rotation of said plug and effective upon rotation of saidplug to move said pin relative to said plug into interlocking engagementwith a contact blade positioned in one of said recesses.

7. In a plug receptacle, a housing of insulating material, an actuatingmember of insulating material rotatably mounted in said housing, saidactuating member having recessesformed therein for the reception of thecontact blades of an attachment plug cap, a boss formed on the iloor ofsaid housing, an L-shaped pin having one arm journaledin said boss forrotation about an axis parallel to the axis of rotation of said plug,depending ribs on the lower face of said plug for engaging the other armof said L-shaped pin for rotating said pin when said plug is rotated,the axes of rotation of said pin and plug being spaced apart wherebyrotation of said plug causes relative movement between said pin and saidplug.

8. In a plug receptacle, a housing, an actuating member of insulatingmaterial rotatably mounted in said housing and having a tapered grooveon the lower face thereof, and locking means pivotally mounted in saidhousing with at least a portion thereof positioned in said groove andadapted to be rotated by rotation of said member, the axes of saidmember and said locking means ybeing spaced apart transversely wherebyrotation of said member causes relative transverse movement between saidmember and said locking means, said groove being substantially the Widthof said locking means at one edge of said member to prevent relativecircumferential movement `having an opening therein, a plug ofinsulating material rotatably mounted in said receptacle body with oneend in engagement with said boss and the other end journalled in saidopening, said insulating plug having recesses formed on the outersurface thereof for the reception of the contact blades of an attachmentplug cap, a locking member pivotally mounted on the face of said bossand extending along the lower face of said insulating plug, spacedprojections on the lower face of said plug for engaging said lockingmember and eiTective when said insulating plug is rotated to rotate saidlocking member, the axes of rotation of said locking member and saidplug being spaced apart whereby rotation of said plug moves said lockingmember transversely with respect to said plug and into lockingengagement with a contact blade positioned in one of said.

recesses.

GEORGE B. BENANDER.

